Home Made Infusoria. Has Anyone Done It?

My celebes fry seem to be doing ok and are slowly growing, feeding on the micro organisms living on the plants and on the almond leaves I assume but as they're getting bigger I thought to include some infusoria to their diet.

I've watched several tube films of how to make your own infusoria and as I type there's a glass of tank water on the windowsill with old spinach leaves (i didnt have any lettuce leaves) and a bit of ripe banana skin in it festering away for want of a better description.

Apparently I need to wait until the water clears , I confess to being a bit nervous about using it so I was wondering if anybody here has grown their own?

Thanks Sue, I'll try those after, I did see these for sale on ebay but I genuinely think that atm they might be too big for the fry.